1. Field of the Invention
The present invention relates to a vehicle power-generation control apparatus that positively implements regenerative power generation when the speed of a vehicle is reduced.
2. Description of the Related Art
With regard to conventional power-generation control apparatuses, especially to a vehicle power-generation control apparatus that positively implements regenerative power generation when the speed of a vehicle is reduced, as disclosed in Patent Document 1, there exists a vehicle power-generation control apparatus that reduces the rate of charging of a secondary battery from a power-generating apparatus as the vehicle speed rises, and increases charging through a regenerative electric current.
The conventional apparatus disclosed in Patent Document 1 makes it possible to recover, without loss, regenerative energy that is approximately in proportion to the square of the vehicle speed, whereby the consumption of fuel required to make a vehicle travel can considerably be reduced.
In addition, torque control at a time when regenerative power generation is performed relates to an electric vehicle; however, as disclosed in Patent Document 2, there exists an apparatus configured in such a way as to implement variable control of regenerative braking force in accordance with the operation of a manual switch only when the accelerator pedal and the brake pedal are not operated.
In the case of the conventional apparatus disclosed Patent Document 2, the regenerative braking force can be adjusted in accordance with the driver's preference so that when the driver desires sufficient braking, sufficient regenerative braking force is securely exerted.
[Prior Art Reference]
[Patent Document]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-58111
[Patent Document 2] Japanese Patent Application Laid-Open No. H8-163706
In the case of the foregoing conventional apparatus, before the regenerative power generation is implemented while the vehicle travels, the charging rate of an electric storage device is kept low, and especially, the power-generation amount is not limited while the brake is operated; therefore, although it is within the tolerance range of the electric storage device or the electric power generator, a large current flows during the time of initial regenerative power generation, and the power generation torque becomes large, as well. However, when on a long descending slope or the like, the electric storage device is fully charged and hence the electric power generator stops generation of electric power, the power generation torque steeply decreases; thus, a shock may occur or a change (decrease) in the feeling of deceleration may deteriorate the drivability.
In addition, even in the case where the driver can set the regenerative braking force, if the charging rate of the electric storage device is not specified at the time of the setting, it is uncertain whether or not the braking force expected by the driver can be obtained when the charging rate differs from the charging rate at the time of the setting; in contrast, because it makes the apparatus and the operation complex, implementation of the setting corresponding to the charging rate of the electric storage device is not realistic.
In addition, the power-generation control is not especially referred to, which is performed after the regenerative power generation has been completed in a situation where the regenerative electric power amount is insufficient due to decrease in the regenerative power generation amount caused by the foregoing limitation of the regenerative braking force, a short regenerative power generation period, or the like.